Efforts to combat dengue fever have improved significantly following the successful results during the testing of a new vaccine. After examining the data from a large clinical trial spanning eight countries, scientists working at the research labs of Japanese pharmaceutical firm Takeda have indicated that the vaccine can protect people from the viral disease.
A total of 20,000 people drawn from Sri Lanka, the Dominican Republic, Nicaragua, Panama, Philippines, Thailand, Colombia and Brazil received the vaccine during the trials. The disease is caused by four types of the Dengue virus, which is transmitted to humans by Aedes aegypti and Aedes albopictus mosquitoes that feed on blood during the day.
Like their Anopheles mosquito counterparts that spread malaria, the insects are found in areas with stagnant water, poor sanitation and uncollected garbage.
Disease symptoms vary with the age of the patient, from mild or hardly noticeable symptoms, to fever, joint pains, rash, pain behind the eyes, nausea and vomiting. Severe fever can lead to bleeding under the skin, nose, passing blood in faeces and even death if left untreated. Dengue fever infects roughly 390 million people and kills 25,000 people around the world each year.
In Kenya, dengue fever outbreaks have been reported in parts of the coastal region and the Rift Valley, with the last outbreak occurring in September in Tirioko Ward, Tiaty sub county, Baringo County. Although the vaccine was found to have an efficiency rate of 80.2 per cent in the study, scientists are still expressing their doubts on its safety.
In 2016, 1 million children in the Philippines received a vaccine known as Denvaxia developed by Sanofi. The firm abandoned the vaccine in 2017 after admitting that it could actually spark severe, deadly forms of dengue fever in about 1 per cent of the children that were vaccinated after being infected with disease.
Takeda’s vaccine is however based on a weakened strain of the Dengue 2 virus, and is reported to be effective against all four strains.
Takeda’s research team led by Derek Wallace, believes the vaccine “can still have a public health impact.”